Many fluid-based applications use some type of device to identify the existence of a leak somewhere in the relevant system. One such application is in the water distribution system for a house or other building structure (e.g., offices). Another involves fuel storage or distribution systems where at least part of the system is stored underground. Yet another application is irrigation systems where relatively large quantities of water are distributed to crops or the like. There are of course many other fluid-based applications where leak detection is desirable or required.
In some cases, the leak detection system exists principally because leaks cannot be readily detected. This is the case in underground fluid flow/storage applications where a visual inspection is not possible, as well as in those cases where a visual inspection is possible but where small leak rates are not readily visually discernible but are in fact important to identify. Other leak detection systems exist so that appropriate actions may be more readily initiated when the leak is detected. Leak detection systems can of course be designed with both of these parameters in mind.
Some leak detection systems are designed to detect a flow condition when there should be no flow. Other leak detection systems are available to detect a leak in a fluid system in which there is a fluid flow. Flow meters are used in both of these instances. Generally, the flow meter will sense an increase in the flow rate (whether from a zero flow condition to at least a certain flow condition, or from a predetermined/preset flow condition to an increased flow condition). Sensing of the increase in the flow rate will typically cause an electrical signal to be sent to some type of control circuit, and this control circuit will in turn send an electrical signal to a valve which will then shut to terminate the flow.
Existing leak detection systems suffer from a number of disadvantages. Some systems are quite complex which obviously increases the cost of the system. For instance, many leak detection systems require their own power source and controller. Increased complexity of the leak detection system can also make integration of the leak detection system into the fluid system more complicated than desired. Other leak detection systems are not what may be termed "generic." That is, some leak detection systems are designed for use with only certain flow rates or a very limited range of flow rates, and may not be appropriate or at least may not be readily adaptable for other applications having significantly different flow rates. Finally, some leak detection systems have an automatic reset feature. Although this may be appropriate for some applications, it is not necessarily appropriate for others.